The present invention relates to an assistance apparatus for a surgical operation, and in particular, it relates to a position measuring apparatus for it.
In a surgical operation, including an orthopedic operation, etc., for example, it is very important to conduct the positioning of a surgical tools or appliances, which is operated by a surgeon in the surgical operation, correctly. However, since it is difficult to conduct the positioning of such the surgical tools or appliances only depending upon visual information, which can be obtained by the surgeon from the portion where the surgical operation is done, then a research and/or study has been made on a use of navigation system, as an assistance of positioning of the surgical tools. Thus, in the INTERNET information mentioned below, there is proposed a laser pointing system, using a navigation system applying laser beams therein, wherein the surgeon can conduct the positioning of the surgical tool upon basis of track of the laser beams displayed thereon at hand, but without seeing a navigation display screen of the navigation system, thereby conducting the surgical operation, correctly.
Orthopedics, Osaka University, “Development of a Laser Guidance System”, [online], [searched on Feb. 18, 2003], INTERNET <URL:http://www.med.osaka-u.ac.jp/pub/ort/www/hip/laser-point ing.html>
However, when conducting the surgical operation while indicating the position through the laser beam within a surgical field, sometimes the laser beam is obstructed or cutoff by a portion of a body of a patient or the surgical tools, etc., and in such the case, it is necessary to move the position of an outlet of the laser beam, so that the laser beam is not obstructed or cut off during the surgical operation. In this instance, a positional relationship is shifted between a position indicating means of emitting the laser beam and a position measuring means for measuring the position of the surgical field; i.e., the coordinates of both are shifted, therefore it is necessary to conduct a calibration operation for those coordinates of both to be coincide with each other. Also, when the outlets of the laser beams are moved accidentally or carelessly, it is necessary to conduct the calibration operation, in the similar manner. However, such the re-calibration operation during the surgical operation, it may results into a consumption of time.